Story from here
A bird was hopping on an immense tree having innumerable branches and huge foliage. The branches were laden with fruits of different sizes and shapes. The lone bird chirped and jumped from one branch to another. The sweet taste of fruits made him happy, and his eyes sparkled with contentment and joy. His breast swelled up with the pride of having discovered and enjoyed the sweet fruits.
But soon, the bird tasted a bitter fruit and his joy turned sour; his ego deflated. Cursing the whole tree, he pondered, 'all this is useless; there is no happiness or joy in these fruits. I don't want any of them.' Ah! The glorious feeling of discrimination and renunciation occupied his heart. He looked hither and thither, and his eyes caught sight of a calm and serene looking bird sitting at the top of the tree. That Bird appeared to be in state of meditation, golden effulgence radiating from His countenance that illumined the whole tree including our little bird.
'O my, my! What a dignified composure and wonderful peace! I must go there,' resolved the little one. It flew up for a while, but soon the temptation of juicy fruits hanging from the innumerable branches overpowered his resolve. He thought, 'those fruits on the lower branches were bitter, but these fruits here appear different, sweeter. Let me enjoy a few of these.' Thus, our little friend stopped and pecked at one juicy fruit. And what a wonder! The fruit indeed turned out to be very sweet. Soon, forgetting the past experiences of repulsive bitter tastes, forgetting everything about that Golden Bird above, this little bird got busy in relishing the sweetness of fruits and cool comfort of green foliage.
However, the story was repeated; it had to. For, the fruits although appearing healthy, juicy, and fresh were but a mixture of sweet and bitter. The bitter taste once again caused dejection, and once again there arose an intense desire to reach the Bird at the top. Repeating such cycles of which no account can ever be kept, at last the lower bird reached the treetop. Approaching the Graceful Bird with a mixture of fear and awe, respect and humility, the lower bird realized to his surprise that he was but the reflection of that Golden Bird! He also acquired that golden hue, that state of peace and bliss, which he had never experienced in its life before. At last, as he reached nearer and nearer to that Bird our friend became one with It, losing his own identity forever.